MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kim, H.
Right arrow Articles by Baumann, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kim, H.
Right arrow Articles by Baumann, H.

Mol Cell Biol, March 1998, p. 1525-1533, Vol. 18, No. 3
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Protein Tyrosine Phosphatase 2 (SHP-2) Moderates Signaling by gp130 but Is Not Required for the Induction of Acute-Phase Plasma Protein Genes in Hepatic Cells

Hongkyun Kim,1 Teresa S. Hawley,2 Robert G. Hawley,2 and Heinz Baumann1,*

Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York 14263,1 and Oncology Gene Therapy Program, The Toronto Hospital, Toronto, Ontario M5G 2M1, Canada2

Received 29 August 1997/Returned for modification 30 September 1997/Accepted 17 November 1997

Signals propagated via the gp130 subunit of the interleukin-6 (IL-6)-type cytokine receptors mediate, among various cellular responses, proliferation of hematopoietic cells and induction of acute-phase plasma protein (APP) genes in hepatic cells. Hematopoietic growth control by gp130 is critically dependent on activation of both STAT3 and protein tyrosine phosphatase 2 (SHP-2). To investigate whether induction of APP genes has a similar requirement for SHP-2, we constructed two chimeric receptors, G-gp130 and G-gp130(Y2F), consisting of the transmembrane and cytoplasmic domains of gp130 harboring either a wild-type or a mutated SHP-2 binding site, respectively, fused to the extracellular domain of the granulocyte colony-stimulating factor (G-CSF) receptor. Rat hepatoma H-35 cells stably expressing the chimeric receptors were generated by retroviral transduction. Both chimeric receptors transmitted a G-CSF-induced signal characteristic of that triggered by IL-6 through the endogenous gp130 receptor; i.e., both activated the appropriate JAK, induced DNA binding activity by STAT1 and STAT3, and up-regulated expression of the target APP genes, those for alpha -fibrinogen and haptoglobin. Notwithstanding these similarities in the patterns of signaling responses elicited, mutation of the SHP-2 interaction site in G-gp130(Y2F) abrogated ligand-activated receptor recruitment of SHP-2 as expected. Moreover, the tyrosine phosphorylation state of the chimeric receptor, the associated JAK activity, and the induced DNA binding activity of STAT1 and STAT3 were maintained at elevated levels and for an extended period of time in G-gp130(Y2F)-expressing cells following G-CSF treatment compared to that in cells displaying the G-gp130 receptor. H-35 cells ectopically expressing G-gp130(Y2F) were also found to display an enhanced sensitivity to G-CSF and a higher level of induction of APP genes. Overexpression of the enzymatically inactive SHP-2 enhanced the signaling by the wild-type but not by the Y2F mutant G-gp130 receptor. These results indicate that gp130 signaling for APP gene induction in hepatic cells differs qualitatively from that controlling the proliferative response in hematopoietic cells in not being strictly dependent on SHP-2. The data further suggest that SHP-2 functions normally to attenuate gp130-mediated signaling in hepatic (and, perhaps, other) cells by moderating JAK action.

* Corresponding author. Mailing address: Roswell Park Cancer Institute, Department of Molecular and Cellular Biology, Elm and Carlton St., Buffalo, NY 14263. Phone: (716) 845-4587. Fax: (716) 845-8389. E-mail: baumann{at}sc3101.med.buffalo.edu.




This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 1998 by the American Society for Microbiology. All rights reserved.